1. Field of the Invention
This invention relates generally to semiconductor processing, and more particularly to semiconductor chips incorporating thru-silicon-vias and methods of fabricating the same.
2. Description of the Related Art
Some time ago semiconductor chip designers began stacking multiple semiconductor dice (aka “dies”) vertically in order to obtain more functionality without an attendant increase in required package substrate or circuit board area. A variety of techniques have been used to electrically connect adjacent dice in such stacked arrangements. One technique has involved the use of wire bonds leading from contact pads on one die to corresponding contact pads on an adjacent die. Another technique that has been introduced more recently involves the use of so-called thru-silicon-vias (TSV). A typical TSV is a conductive via that extends nearly or perhaps entirely through a semiconductor chip, depending on the presence or absence of any intervening conductor pads at one or the other of the principal surfaces of the chip.
A typical conventional TSV provides electrical routing between opposite principal surfaces of a semiconductor chip. On one side, the conventional TSV is connected to some type of input/output structure (I/O), which is often a solder bump designed to form a solder joint with a package substrate during flip-chip solder reflow. The TSV is not connected directly to the solder bump, but to some intervening structure, such as an outermost metallization structure like a bump pad. The other or backside end of the TSV is connected to some form of backside I/O structure, typically through some intermediary conductor structure. The conventional TSV arrangement includes a single TSV metallurgically joined to a single bump pad.
Conventional TSVs are subjected to Joule heating and electromigration issues that vary in intensity depending on power levels, thermal management, die size and other factors. A one-to-one TSV to bump pad arrangement is subjected to such environmental considerations.
The present invention is directed to overcoming or reducing the effects of one or more of the foregoing disadvantages.